The invention relates to a method and apparatus for removing faecal matter from slaughtered poultry suspended by the legs and for cleaning said poultry.
An important objective when slaughtering and processing poultry in, for example, poultry processing plants is the maintenance of hygiene. This hygiene is critical because during the processing of the slaughtered poultry faecal matter is unloaded, which leads to the contamination of the poultry. It has even been shown that faecal matter from one bird in an automated processing line can lead to the contamination of several hundreds of subsequent birds.
Over the years many proposals have been made in an effort to combat such faecal contamination.
A known method of avoiding faecal contamination is to terminate feeding for an extended period of time so that the intestines of the poultry will eventually be vacated. However, this involves several drawbacks. For one thing, the liver of the poultry initially continues to produce bile that will not be used up anymore. This causes the gall-bladder to be stretched increasingly taut, which may increase the risk that when the intestines are being removed, the poultry will become tainted from the bile. In addition, no feeding will have a negative effect on the weight of the poultry. The termination of feeding further leads to the appendix vacating into the colon, so that the faeces are relatively more heavily contaminated than usual, putting a greater strain on hygiene.
Yet another drawback of terminating feeding is that the length of time for which feeding is terminated is difficult to control for each individual chick. This is because termination of feeding starts for a whole batch of chicks at a predetermined moment, while several hours may pass between slaughtering the first chick and the last chick. Apart from producing unpleasant situations for the animals before slaughter, it also increases the number of chickens already dead before slaughter. Termination of feeding further increases stress, which has a negative effect on the quality of the meat.
It has also been proposed to use feed supplements in order to combat the number of bacteria in the excrement. However, a problem with this method is that not all bacteria can be combated equally effectively in this manner.
Another proposal is to supplement the drinking water of the poultry with lactic acid during the period of feed termination. However, this merely results in combating contamination via the gullet and does not effectively combat contamination via the faecal matter.
Yet another proposal is to wash the poultry during bleeding. However, this method also has drawbacks preventing its application. Washing poultry during bleeding is undesirable because the resulting blood/water mixture leads to extra costs for purification (if blood is discharged with the water) or recycling (if water is discharged with the blood).
U.S. Pat. No. 3,137,031 makes the proposal of, prior to evisceration, flushing the lower intestines of the poultry with water while simultaneously evacuating the lower intestines by pneumatic suction. However, this evacuation by suction can easily cause damage to the intestines.
A method of removing faecal matter from slaughtered poultry suspended by the legs in accordance with the preamble of the main claim is known from U.S. Pat. No. 4,739,539. The drawback of this known method is that the intestines are subjected to pressure after the poultry has been scalded and plucked. This results in a continued contamination both during the scalding phase and in the plucking phase of the poultry. A further problem is that the apparatus known from this patent exerts pressure to the breast and the back of the poultry simultaneously by means of two components of the apparatus, each of which rotates about an axis. The result is that this operation takes very little time, which practice has shown to be insufficient to effectively remove the faecal matter from the poultry.
U.S. Pat. No. 4,876,767 proposes an apparatus for evacuating the intestines of the poultry by suction after scalding and plucking. This means that bacteria present on the skin and feathers on the outside of the poultry causes contamination of the scalding water and forms a considerable risk for cross-contaminating the remaining poultry. A further drawback is that, in the stage of evacuation by suction, considerable contamination has already occurred due to the faecal matter that may have unloaded spontaneously during bleeding, during scalding and during plucking. A disadvantage is also that metering the applied vacuum is difficult to the extent that an unacceptable amount of damage to the intestines is incurred. In addition, the suction organ used is susceptible to clogging.
A method and apparatus as proposed in U.S. Pat. No. 4,876,767 is also known from U.S. Pat. No. 4,889,421.
In WO 96/37110 (EP-A-910 249), it is proposed to combat contamination by faecal matter by closing off the anus of the poultry by means of a plug. The use of such a plug or stop is process-technically difficult when applying the customary process of removing the vent. Moreover, this may still cause cross-contamination of successive poultry.
It is a principal object of the invention to provide a method and apparatus for removing faecal matter from slaughtered poultry suspended by the legs in which the above-mentioned drawbacks are reduced or absent. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
To this end, the method for removing faecal matter from slaughtered poultry suspended by the legs is in accordance to the invention characterized in that the pressure to the abdominal cavity of the poultry is applied prior to scalding.
According to the invention, this method may, for example, be conveniently carried out in an apparatus for removing faecal matter from poultry suspended by the legs from an overhead transporter, comprising a presser organ for applying a pressure load to the abdominal cavity of the poultry, as well as a scalding installation, and succeeding the scalding installation, a plucking installation, which is characterized in that in the process direction of the installation, the presser organ precedes the scalding installation.
In order to enhance the effectiveness of squeezing the faecal matter out, the pressure load is, after its application and during its continued application on the abdominal cavity, moved in the direction of the anus of the poultry.
To this end, the effective squeezing out of the faecal matter may be conveniently realized in an apparatus characterized in that the presser organ is a pressure lever that is pivotally suspended from an axis, having a free end for placing against the abdominal cavity of the poultry and in that with an increase in pressure load, the pressure lever moves in the direction of the anus of the poultry. When a high processing rate of birds per hour is required in processing slaughtered poultry on an industrial scale, it is advantageous for the poultry to stay positioned in a suspended vertical position during the application of the pressure load.
It is further desirable that, during the application of the pressure load, the anus of the poultry is simultaneously sprayed with water and/or air. To this end, the apparatus is preferably provided with a spray nozzle directed at the anus.
In another aspect of the invention, it is desirable that after the application of the pressure load but before scalding, the poultry in its entirety is subjected to a washing operation.
To this end, the apparatus is preferably embodied such that, viewed in the process direction, after the presser organ, a spraying chamber is provided for the external cleaning of the poultry. In this manner, the poultry from which the faecal matter has already been removed receives an effective external cleaning by means of thorough flushing, preferably with warm water. This largely removes the external fouling and contamination so as to greatly reduce fouling and contamination in later phases of processing. This is especially important with respect to the scalding water in which the poultry is placed to soften the feathers of the poultry prior to plucking.
For economical reasons it is desirable for the spraying chamber to be incorporated in a recirculation system for the spraying water. The hot water output being sprayed over the poultry may amount to several liters per animal, which makes collecting, filtering, decontamination and re-use of the water economically interesting, while limiting the external harm to the environment. Desirably, the recirculation system comprises a filtering sieve. For the decontamination, the recirculation system advantageously comprises a pasteurizer. If desired, this may be combined with an anodic oxidation, possibly complemented by an ultrasonic treatment of the water. With a view to economic water and energy consumption, it is further desirable that the scalding installation and/or the plucking installation is also incorporated in the recirculation system for the spraying water.
In a completely different aspect of the invention, it is proposed that before or during the application of the pressure load on the abdominal cavity of the poultry, the poultry may be connected to an electrical stimulation system.
Desirably, the electrical stimulation system is adjusted with predetermined settings for voltage, type of signal, frequency and duration of the signal to be emitted by the system. This electrical stimulation system contributes to the spontaneous unloading of the faecal matter. An additional important advantage is that the electrical stimulation provided by this system benefits the tenderness of the meat of the poultry.
Below the invention will be briefly elucidated with reference to a schematic exemplary embodiment based on the appended drawing.